Examine how the concentration of the substrate Hydrogen Peroxide (H2O2) affects the rate of reaction of the enzyme Catalase.

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Introduction

Aims This is an experiment to examine how the concentration of the substrate Hydrogen Peroxide (H2O2) affects the rate of reaction of the enzyme Catalase. Background Information Enzymes such as Catalase are protein molecules, which are found in living cells. They are used to speed up specific reaction within the cell. They are all very specific as each enzyme just performs one particular reaction. Catalase is an enzyme found in food such as potato and liver. It is used for removing Hydrogen Peroxide from cells. Hydrogen Peroxide is the poisonous by-product of metabolism. Catalase speeds up the decomposition of Hydrogen Peroxide into water and oxygen as shown in the equations below. Apparatus Need For The Experiment. 250 cm3 Glass Beakers, Glass Thistle Funnel, Graduated Measuring Cylinder, .Cork Borer,250 cm3 Glass Cylinders , Digital Stop clock, Scalpel, Tap , Distilled Water, Plastic rule, Safety Goggles. Method To test out how the concentration of Hydrogen Peroxide affects the rate of reaction first set up the apparatus and prepare the different concentrations of Hydrogen peroxide as below: Concentration of Hydrogen Peroxide Volume of Hydrogen Peroxide (cm3) ...read more.

Middle

This gives the rate in cm3 of oxygen produced in the time of 5 minutes, this is because I am timing how much oxygen gas is given off in the space of 5 minutes for the various concentrations of Hydrogen Peroxide. From these results, a graph can be plotted with concentration on the x-axis and the volume of gas released on the y-axis. To ensure this experiment is completed as fairly as possible, all the variables except for the concentration of Hydrogen Peroxide must be kept the same for all experiments. Variables that must not be altered include: Temperature, Catalase Concentration, dimensions of potato, air pressure and humidity. When measuring the volumes of water and Hydrogen Peroxide, the measurement should be taken from a 90-degree angle to avoid parallax error. Predictions I predict that as the substrate concentration increases, the rate of reaction will go up at a directionally proportional rate until the solution becomes saturated with the substrate Hydrogen Peroxide. ...read more.

Conclusion

For example: 1. There is a slight delay between pouring the thistle funnel with the potato discs into the beaker of Hydrogen Peroxide. This will slightly affect all the results for each individual experiment but as I carried out all the steps in the same way, it should not make any negotiable difference to the overall result. 2. It is also impossible to precisely measure out the amounts of Hydrogen Peroxide and Distilled Water each time. As the scale on the measuring cylinder shows the measurement to the nearest 1mm3, the solutions that I used should be correct to the nearest mm3. Ways to Improve Experiment. As using catalase founded in potatoes, the desired amount was hard to measure, however, measuring the amount of potato wasn�t difficult although that piece could contain different amounts of catalase compared to another piece. The results that would show from both pieces would be negotiable. Maybe having a source of catalase from yeast would have been much more easier to use and handle. Specific amounts could be measured much more precisely. ...read more.

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* Apparatus- The apparatus will not be changed at all, apart from the use of different syringes for the Hydrogen Peroxide and Yeast respectively. I will be taking three readings at each concentration, in order to obtain more accurate results.

The skin of the potato will be removed. The experiments be carried out at room temperature and will be monitored with a thermometer. I will throughout all my experiments keep consistence and the same order of perpetration. If these variables were not controlled I would not get accurate results because there would be no consistence and results may differ due to change in variables.

* When a slice of potato is placed into a solution of hydrogen peroxide, bubbles of oxygen form on the potato surface and rises to the top of the solution. Potatoes contain catalase, an enzyme that breaks down hydrogen peroxide into water and oxygen.

The graph would look like this: Concentration of enzyme If you increase the concentration of the enzyme, the rate of reaction will be quicker. This is because there is more enzyme and so more molecules per cm�, which means there's a higher chance of he molecules colliding with the substrate molecules.

which oxygen gas is produced once the hydrogen peroxide has come into contact with the catalysing enzyme catalase will be the simplest way of measuring the rate of the reaction. There are a number of possible methods that I could use to measure the rate at which gas is produced,

if the chips are small but there are a lot of them there will be more area for the hydrogen peroxide particles to collide with. This increase in the frequency at which the two particles collide means that the reaction becomes faster.

Furthermore, some people may be allergic to the enzymes if they are left on the clothes, and so this is a flaw in its production, but it can be argued that some people could still be allergic to substances found in natural detergents, and they do not work as effectively.